Melamine Cleaning Compounds

In theory, you then pull the finished encapsulated semiconductor out of the mold cavity and put the next set of semiconductor components in and repeat. However, in practice, stains build-up on the surface of mold die, particularly in the nooks and crannies and along the edges of the cavity. Over time the layer of residue thickens so much it forms a burr along the periphery of the cavity and negatively impacts the quality of the finished part. That's why cleaning and conditioning your molding tools can prevent molding defects.

However, over time the internal release agent forms a residue, along with other contaminants, and gets trapped in the microporous structure of the metal mold, and eventually oxidizes to form a hard layer. This is the main origin of mold die stains. Other sources include epoxy residue, resin bleed, and solder flux residue.

Eventually this layer of oxidized internal release agent builds up on the mold tools surface: contributing to mold defects, loss of glossy surface quality on the part, and ironically making it harder to release the part from the mold! So obviously, after a certain number of runs, every semiconductor molding operation needs some down time to clean the molds.

On the other hand, regularly cleaning involves some downtime for some machines, but, in general, production can keep going. The faster you clean the mold the less downtime you will have, and this is the most important factor when trying to fit a cleaning procedure into your production cycle.

A copper brush and some manual labor is still one of the most effective cleaning methods. However, with a mold at 180c or more, how effectively can any line technician really be? And do you really want to turn the mold off to let it cool, then clean it, and then bring it back up to temperature? That would mean hours of downtime. If you have to, then you have to, but there are alternative ways of cleaning the mold die that require less downtime.

Melamine cleans the mold by adhering to stain and peeling it off the surface of the mold when Melamine is peeled off. It also contains an abrasive filler which grinds and attacks stains as it flows through mold die channels and cavities. Another important way it attacks stains is with additives which dissolve the stain and bind it to the Melamine. This reduces the phase boundary between the stain and the mold: allowing the stain to come off more easily when you peel the cured melamine out of the mold cavity.

The semiconductor industry as a whole is, however, moving away from Melamine as a mold cleaning compound. That is because cured Melamine is hard to remove from mold cavities and it produces formalin as it cures. Formalin is an aqueous form of Formaldehyde, and so the vapors produced by Melamine cleaning compound are carcinogenic and very dangerous for human health.

Regulations such as the EU’s REACH places formaldehyde on the substance of high concern list. This makes importing and using Melamine quite legally challenging in some situations. That’s why CAPLINQ’s R&D department is working on developing a new Melamine compound with less than 0.1% formaldehyde to make it meet REACH standards, as well as formaldehyde-free formulations for our melamine cleaning compound.